Seat post removal

Tried almost everything to get the post out. Long aluminium seat post on a steel frame with no grease = bad times. Tried blow torching, plus gas, put the seat in a bench vice and using the whole frame as a lever. Only solution was to drill it out or melt it out. Being a keen scientist I went for the melting. Bought two bottles of Caustic soda (sodium hydroxide) from nearest hardware store and funnelled it down the seat tube from the bottom bracket. The bike was hung upside down in my garage with a bucket underneath. I emptied it out once per day for a week and kept topping it up when the reaction stopped. Sodium Hydroxide will dissolve aluminium but doesn't affect steel. Eventually the hydroxide melted its way through the post and I was able to pull the remainder of the post out and flush the bike with water.